Description:

A central goal in ecology is to identify general relationships between environmental drivers and community patterns. In this study, we investigated the relationships between aquatic invertebrate communities and river flow intermittence across multiple continents. Particularly, we hypothesized that resilience (dispersal) rather than resistance (desiccation-resistance forms) mechanisms explain the patterns of aquatic invertebrate communities in intermittent rivers. Hence, we predicted a general decrease in invertebrate taxonomic richness with increasing flow intermittence and community nestedness to occur systematically along flow intermittence gradients. We tested these predictions using 14 datasets from intermittent rivers in Europe, North America, and New Zealand, presenting varying flow intermittence ranges and spatial arrangements of perennial and intermittent reaches. We demonstrate that invertebrate communities had remarkably congruent patterns along flow intermittence gradients. These general responses were largely driven by resilience mechanisms, and the different spatial arrangements of perennial and intermittent reaches did not strongly affect the observed patterns.

Purpose/Objective:

This metanalysis investigated the role of river drying on taxonomic diversity of riverine invertebrates. We demonstrated that the relationship between inverebrate communities and flow intermittence (proportion of the year rivers were dry) was consistent across rivers from a wide range of sizes and from multiple continents. Our analyses also indicated that resilience (dispersal capacity) rather than resistance (capacity to persist in place) explained diversity patterns across the flow intermittence gradients. The relationships we generated will help water managers from around the world mitigate the effects of dams, flow diversion, and water abstraction, and also help predict future changes to riverine biodiversity.